Lightweight and Mechanically Robust Cellulosic Triboelectric Materials for Wearable Self-Powered Rehabilitation Training.

Lightweight and robust self-powered wearable devices are of great importance in rehabilitation and medical assistance, but this places greater demands on the development of functional materials. In particular, a balance between reducing the weight of materials and enhancing their mechanical performance is urgently needed. Here, this study reports a design strategy based on a cross-scale strengthening mechanism, which endows triboelectric materials with mechanically robust properties, and can withstand more than 16,600 times its weight without any deformation. A biomimetic ordered network structure with "wall-septum" is obtained by using the directional ice templating method, followed by the formation of more hydrogen bonds between polymer molecular chains promoted by salting-out. The resultant triboelectric material exhibits a Young's modulus of 130.3 MPa, and a specific modulus of 409.0 kN m/kg. Triboelectric materials are used to construct highly robust triboelectric nanogenerators that are stable even under an impact of 735.5 kPa. The accurate acquisition of a human motion state signal in the process of rehabilitation training is realized. This study provides a universal strategy for the development of lightweight and robust triboelectric material and provides a solution for the application of self-powered wearable devices in rehabilitation training.